PROJECTION OPTICAL SYSTEM AND PROJECTION EXPOSURE APPARATUS

摘要

This projection optical system is equipped with a condensing power lens group and a divergent power lens group having a refractive index temperature coefficient with the same sign as that of the condensing power lens group. The condensing power lens group includes a lens with a focal point distance of 1 m or less, and the lens with a focal point distance of 1 m or less is arranged separated from the adjacent lens by an air space of ten percent or less of the focal point distance.